A convection battery uses flow of electrolyte between a flow-permeable electrode and its flow-permeable counter-electrode through a flow-permeable separator to improve mass transfer. Flow between electrodes and their counter-electrodes in a battery improves ion mass transfer between the pairs. The counter-electrode is an electrode that is of opposite polarity and functionally coupled with an electrode; the counter-electrode is defined with implicit reference to an electrode with which it is paired and consistent with methods known in the art.
Improved mass transfer results in more voltage being available from the battery and more efficient use of the energy stored in the battery. Increased voltage at high current flux results in increase power both for charging and discharging. Power and power density are key performance metrics. The high limiting ion fluxes in combination with a heat exchanger in the electrolyte circulation loop allows for substantially reduced charging times for batteries.
Battery cost is an additional metric important to customers. Methods of assembling batteries impact the costs of batteries. Spiral-wound fabrication methods are recognized as being less expensive than alternative methods of manufacturing batteries. The advantage of improved mass transfer can manifest as a reduced separator surface area between electrodes with resulting thicker electrodes while keeping the limiting current the same, which reduces the costs further. Reduced current collector areas and costs, and reduced costs associated with coating the separator/membrane, also, manifest. Alternatively, higher fluxes can lead to higher limiting currents when the separator area is kept constant. This reduces charge times of a battery which is a highly favorable quality.
Higher flux batteries can be used to produce an optimal combination of higher limiting currents, reduced costs, and reduced dendrite failure susceptibility as compared to batteries without convective flow of liquid electrolyte between electrodes.
Energy density is an additional metric important to many customers. It is recognized that lithium-metal technologies that would eliminate dendrite modes of battery short-circuit in lithium chemistry batteries would have high energy densities.
The embodiments of this invention are applicable to convection batteries as well as other electrochemical devices.